The Felhunter ability Spell Lock is now an interrupt, and no longer applies a 3 second blanket Silence.

Blood Fear has been redesigned. This ability is now cast on the Warlock, and causes melee attacks that strike within the next 60 seconds to Fear the attacker. When cast, the ability has 1 Charge, costs 20% health to activate, and has a 30 second cooldown.

Soul Leech now provides an absorption shield instead of healing.

Sacrificial Pact now requires the pet to sacrifice 25% of its health to activate (was 50%).

Kil'jaeden's Cunning is now a passive talent, and its activated ability has been removed.

The passive damage from Archimonde's Vengeance no longer has a visual effect.

Grimoire of Sacrifice now increases the damage of abilities by 20% (was 25%) for Destruction, and 45% (was 50%) for Affliction.

Grimoire of Sacrifice now provides the spell Whiplash instead of Seduction when a Succubus is sacrificed.

Glyph of Burning Embers has been removed, and its effects are now baseline for Destruction Warlocks.

Glyph of Soul Shards has been removed, and its effects are now baseline for Affliction Warlocks.

New Glyph: Glyph of Ember Tap. This glyph increases the healing gained from Ember Tap by 50%.

New Glyph: Glyph of Drain Life. This glyph increases the healing gained from Drain Life by 30%.

There'll be countless more changes no doubt, but let's keep the general 5.2 changes discussion in this thread. I'll try to add to the OP as new builds of the PTR go out.

Fel Armor now reduces damage taken by 10%, rather than increasing armor.
Unstable Affliction now does 14% more damage when dispelled. This damage always critically strikes.

Talents

Blood Fear now costs 5% of Total Health, down from 20%.
Burning Rush - During Burning Rush, movement-impairing effects may not reduce you below 100% of normal movement speed.
Sacrificial Pact now shields for 400% of the sacrificed health, up from 200%.

Affliction

Unstable Affliction now does 14% more damage when dispelled. This damage always critically strikes.

Major Glyphs

Glyph of Ember Tap has been reworked: Ember Tap heals you for an additional 5% of your health, but the health is restored over 10 sec.
Glyph of Unstable Affliction now reduces the cast time of Unstable Affliction by 25%.

• Fel Armor has a significant typo in its tooltip; we added the 10% damage reduction and took away the armor. The health and healing received are still increases, not decreases.

• The new Glyph of Unstable Affliction reduces the cast time, but does not affect the GCD. Thus, it is not a DPS gain in a purely Patchwerk situation, but makes it harder to be interrupted, and allows you to start moving again slightly faster.

• The Affliction Warlock 4T15 bonus increases the damage of Malefic Grasp itself, and the extra ticks triggered by it. Same with Drain Soul.

About Destro and the "bug" where you are now NOT getting 2 embers refunded when you kill something with Shadowburn (which has been something that propped up Destro's DPS in tier 14 to an acceptable level) but on the PTR only get 1 refunded.

Originally Posted by Blizzard Entertainment

We thought we did fix it. Any more information? It costs 1 ember, but if it kills the target or the target dies within 5 sec, it restores 1 ember, for a net costs of 0. If it ever restored 2 embers on a kill, that was a bug and probably got fixed.

Warlock
- We are going to go ahead and grandfather in the bug of Shadowburn granting 2 embers on a kill. It is technically a bug, which is why we fixed it, but it's been that way since MoP launched and we don't think it's causing huge balance problems, so in cases like this, we think the right thing to do is just make it official.

Grimoire of Sacrifice (Affliction) now increases the power of many of your single target spells by 35%, down from 45%.
Grimoire of Sacrifice (Destruction) now increases the power of many of your single target spells by 15%, down from 20%.

Fel Armor now reduces damage taken by 10%, instead of increasing the Warlock’s armor.
Blood Fear has been replaced by Blood Horror. Blood Horror costs 5% health, has 1 charge, and lasts 60 seconds with 30-second cooldown. While Blood Horror is active, melee attacks that strike the Warlock will cause the attacker to be horrified for 4 seconds.
Burning Rush now also prevents movement-impairing effects from reducing the Warlock’s movement speed below 100% of normal, in addition to its other effects.
The Imp ability Blood Pact has been removed.
Dark Intent now increases Stamina in addition to Spell Power.
Immolate now deals 15% more damage.
Shadow Bolt now deals 15% more damage.
Soul Leech now provides an absorption shield instead of healing.
Sacrificial Pact now requires the pet to sacrifice 25% of its health to activate (was 50%).
Kil'jaeden's Cunning is now a passive talent, and its activated ability has been removed.
The passive damage from Archimonde's Vengeance no longer has a visual effect.
Grimoire of Sacrifice now increases the damage of abilities by 15% (was 25%) for Destruction Warlocks and 25% (was 50%) for Affliction Warlocks. In addition, it now provides the spell Whiplash instead of Seduction when a Succubus is sacrificed.
Glyph of Burning Embers has been removed and its effects are now baseline for Destruction Warlocks.
Glyph of Soul Shards has been removed and its effects are now baseline for Affliction Warlocks.
New Glyph: Glyph of Ember Tap. This glyph increases the healing gained from Ember Tap by 33%, but the health is restored over 10 seconds.
New Glyph: Glyph of Drain Life. This glyph increases the healing gained from Drain Life by 30%.
Glyph of Unstable Affliction has been redesigned. This glyph now reduces the cast time of Unstable Affliction by 25%.
Affliction

Haunt now causes the target to receive an additional 30% damage (was 25%) from Warlock's spells.
Unstable Affliction’s backlash effect is now always a critical hit and deals approximately 15% more damage.

Demonology

Chaos Wave now has a new visual.
Hand of Gul'dan now deals 15% more damage.
Shadowflame now deals 15% more damage.
Soul Fire now deals 22% more damage.
Touch of Chaos now deals 15% more damage.
Wild Imp's Firebolt now deals 15% more damage.

Destruction

Conflagrate now deals 15% more damage.
Fire and Brimstone now has a radius of 10 yards (was 15 yards).
Incinerate now deals 10% more damage.

Last edited by xskarma; 2013-03-05 at 04:00 PM.
Reason: update 5th March

As we guessed, nerfs to GoSac for demo and affli. Reduce to 20-45% damage increase from original 25-50%

Also:

Glyph of Drain Life Increases the healing of your Drain Life by 30%.
Glyph of Ember Tap Increases the healing of your Ember Tap by 50%.

Does this mean that 4 shards and embers will become baseline?

Yeah, pretty much, there was litterally noone NOT taking them, and they were pretty much mandatory. I forgot to add the Affli & Demo GoSac changes, I think I'll add those to the OP, cause that's pretty fucking HUGE change.

Hmm, that change to Blood Fear happens to be exactly what I've been suggesting.

Did you also read the 20% health cost part? Because I don't think any rational person would suggest to put such a steep cost on such a mediocre talent. Even without the health cost it is already a major nerf, I have no idea why they felt the need to make it even crappier.

Don't know what to think about Soul Leech and I'm not sure if Sacrificial Pact really needed to be nerfed in half though...

Can only hope that the absorb stacks as opposed to 'biggst ability in the last 15 seconds'. I imagine the damage component will be nerfed to like 5% if it does stack since unlike the heal which is useless at full health you could keep rolling an absorb in a no damage phase until your eventually hit. Probably be capped at a % of your health too like 20%.

Sac pact i guess needed a nerf though I'll be very sad to see it go. I would have prefered them just lopping off a minute on dark bargain though in all honesty. Atm sac pact just gives you a crazy absorb shield on a minute cd. Especially very cool for demo as pets get healed up pretty quick so not even the self 'harm' from it.

So they remove blanket silence, blood fear and put the final blow on enfeeblement without compensating. Meanwhile they throw buffs at rogues again. How can they not see that rogues have WAY more utility than warlocks as it is? I don't understand how they can get so much more love when both have been equally bad (besides the short time demo was the shit). Didn't locks complain enough or what's up with this? I'm glad I don't PvP on my toon.

GoSac changes seems fine. They've been doing their best to try avoid cookie cutter builds so this is good. Same with soul shard/burning ember glyphs if they become baseline.

I did expect some bigger nerfs for Affli's damage output. Maybe I've been overestimating the spec.